Leland Stanford Junior University

Andrew J Merriam

Guang-Yu Yin

Stephen E Harris

Scott J Sharpe

Hui Xia

A self-seeding laser comprises a slave oscillator cavity coupled to a Littman cavity that operates in a single longitudinal mode. The slave oscillator cavity comprises the following elements positioned in sequential order to provide a first beam path: an end mirror, a gain medium, a grating having a groove spacing, and an output mirror. The first beam path has an angle of incidence upon the grating, and light traveling along the first beam path is zeroth-order diffracted by the grating. A tuning mirror faces the grating, for reflecting light diffracted away from the first beam path by the grating. The tuning mirror establishes the Littman cavity. The gain medium is pumped by a pulsed pump beam. The pump beam activates a pump region within the gain medium, the pump region having a radius. The Littman cavity operates in the single longitudinal mode because the angle of incidence, the groove spacing, and the radius are adjusted so that an adjacent mode walk-off time of the Littman cavity is less than a mode build-up time of the Littman cavity. A gain in the Littman cavity is initially greater than a gain in the slave oscillator cavity; the laser is thereby self-seeded in the single longitudinal mode.

Method and apparatus for single longitudinal mode operation of pulsed laser oscillators using efficient self-seeding

A method for producing electromagnetically induced transparency (EIT) in atoms with hyperfine structure. EIT is the phenomenon in which a material (e.g. lead vapor) becomes transparent to a first electromagnetic frequency (a probe beam) when exposed to a second electromagnetic frequency (a coupling beam). In the present invention, the atom has hyperfine split energy levels. In the method of the present invention, the coupling and probe beams are tuned to transitions between the centers of gravity (COGs) of the hyperfine split levels. This allows high transparencies to be achieved in high opacity materials. Also, the present method can produce EIT in isotopically mixed materials. This is because the COGs of hyperfine split levels (in nuclear spin.notident.0 atoms) are generally coincident with nonhyperfine split levels (in nuclear spin=0 atoms). The method of the present invention is directly applicable to nonlinear sum and difference frequency generation.

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Palo Alto, CA, United States of America

Andrew J Merriam